Asymmetric spatiotemporal patterns of event-related desynchronization preceding voluntary sequential finger movements: a high-resolution EEG study.

OBJECTIVE To study spatiotemporal patterns of event-related desynchronization (ERD) preceding voluntary sequential finger movements performed with dominant right hand and nondominant left hand. METHODS Nine subjects performed self-paced movements consisting of three key strokes with either hand. Subjects randomized the laterality and timing of movements. Electroencephalogram (EEG) was recorded from 122 channels. Reference-free EEG power measurements in the beta band were calculated off-line. RESULTS During motor preparation (-2 to -0.5s with respect to movement onset), contralateral preponderance of event-related desynchronization (ERD) (lateralized power) was only observed during right hand finger movements, whereas ERD during left hand finger movements was bilateral. CONCLUSIONS For right-handers, activation on the left hemisphere during left hand movements is greater than that on the right hemisphere during right hand movements. SIGNIFICANCE We provide further evidence for motor dominance of the left hemisphere in early period of motor preparation for complex sequential finger movements.